The present invention relates to disklike recording media, such as CD (i.e., compact disk) and DVD (i.e., digital video disk or digital versatile disk), which are suitable for mass production and wide-area distribution. More specifically, the present invention relates to an anti-forgery system, and related detecting apparatuses installable in the distribution channel or in a center office equipped with a host computer. Moreover, the present invention relates to a manufacturing method and apparatus for recording the information for a true-false judgement on the surfaces of the disk.
The conventional CD is preferably used for recording the audio information or program. The conventional VHD or LD is preferably used for recording video or image information. However, a recently developed DVD has a very large recording capacity which is approximately 5 to 7 times the recording capacity of the above-described conventional disks. Thus, the CD, VHD and LD will be replaced by DVD-Audio and DVD-Video.
In other words, the high-density recording media can provide an added value due to their large recording capacity. On the other hand, the industrial damage and monetary loss will be very large if they are subjected to the forgery.